Ventilation device for a fuel tank

ABSTRACT

The invention relates to a ventilation device for fuel tanks, wherein the ventilation device comprises a compensator reservoir arranged in the interior of the fuel tank and at least two ventilation lines. The ventilation lines run from below the upper tank wall to the compensator reservoir and extend in the latter toward an opposite tank wall. The apparatus according to the invention is particularly well suited under all static and dynamic stresses for ventilating fuel tanks.

FIELD OF THE INVENTION

[0001] The invention relates to a ventilation device for a fuel tank ofa motor vehicle, wherein the ventilation device comprises a compensatorreservoir and at least two ventilation lines opening into the latter.

BACKGROUND OF THE INVENTION

[0002] A ventilation device is used to remove the gases displaced byfuel entering a fuel tank during “tanking up” and the gases that areemitted from the fuel during the operation of a motor vehicle. For thispurpose, one or more lines are situated below the upper fuel tank wall.These lines lead from the sides of the tank to a common location atwhich they pass through the tank wall and lead to another tank.

[0003] A ventilation device may have two ventilation lines and threecompensator reservoirs is known. The ventilation lines open out on bothsides of the tank. From there, they lead to the opposite side of thetank and curve back again into the center where they open into a centralcompensator reservoir. In the curved sections near the side walls thelines include a widened section which is likewise designed as acompensator reservoir. This line routing has the effect that when thetank is inclined ventilation is ensured. One disadvantage is that thisdevice is only suitable for tanks of relatively simple construction.Another disadvantage is that the routing of the ventilation lines isvery complicated because of the labyrinth-like course the lines musttake. Further disadvantages, caused by the inclusion and arrangement ofa number of compensator reservoirs, include that the device iscomplicated to manufacture and that the installation of the device in afuel tank requires a high outlay.

SUMMARY OF THE INVENTION

[0004] The invention provides a ventilation device which is of simpleconstruction, can be installed easily and ensures reliable ventilationand maximum filling of the fuel tank under all circumstances.

[0005] The ventilation device may be used in a fuel tank. In oneembodiment it comprises a compensator reservoir in the fuel tank and atleast two ventilation lines opening into the compensator reservoir. Inthis ventilation device, the ventilation lines run from the vicinity ofat least one of the side walls of the fuel tank to the compensatorreservoir. Advantageous refinements are also disclosed herein.

[0006] The ventilation device includes a compensator reservoir which isarranged in the interior of a fuel tank and into which at least twoventilation lines open. The fuel tank includes a first side wall and asecond side wall. The compensator reservoir extends from the first sidewall to the second side wall of the fuel tank. The ventilation linesinclude a first opening and a second opening. The ventilation lines arearranged such that at least one of the first openings of the ventilationlines is always situated above the fuel level for all possible inclinedpositions of the fuel tank. The ventilation lines extend from thevicinity of one of the side walls to the vicinity of the other sidewall, wherein the first opening is in the fuel tank and the secondopening is within the compensator reservoir.

[0007] The ventilation device, therefore, enables reliable ventilationfor static and dynamic stressing of the fuel tank and at the same timepermits a particularly high filling quantity in the fuel tank. Moreover,the geometrical configuration of the compensator reservoir makes simplerouting of the ventilation lines possible, with the result thatcomplicated return lines are superfluous. At the same time, only onecompensator reservoir is necessary. Because of its simplicity, theentire ventilation device is distinguished by low production costs, lowweight and simple installation.

[0008] The compensator reservoir advantageously has a widened sectionwhich is used as a liquid trap and via which any fuel which has passedinto the compensator reservoir is sucked into the interior of the fueltank, preferably via an ejector or directly via the fuel pump. To ensurethat the ejector or fuel pump does not allow the compensator reservoirto be filled to overflowing when, for example, the vehicle is parked ona slope, a nonreturn valve is used in the extraction line of the widenedsection.

[0009] The ventilation device is particularly simple if the ventilationlines enter into the compensator reservoir at any desired location,preferably at the widened section, and are then guided in thecompensator reservoir until they are close to the side wall opposite theside wall in the vicinity of the first opening of the ventilation line.When the ventilation lines are arranged diagonally, the above-describedsystem ensures satisfactory ventilation of the fuel tank at maximumfilling level and due to the static and dynamic stresses, optimallyprevents the fuel tank from being filled to overflowing.

[0010] Depending on the shape of the tank, the diagonal ventilationarrangement can also be formed using four predominantly diagonalventilation lines while retaining the abovementioned, positiveproperties. In this case, the ventilation lines are arranged starting inthe corners of the fuel tank and running diagonally toward thecompensator reservoir. The compensator reservoir may be arranged in anydesired manner with respect to the longitudinal axis of the vehicle andmay also be of x-shaped design with the individual arms of thecompensator reservoir extending toward the ventilation lines.

[0011] It is furthermore advantageous if the compensator reservoir has afloat/roll-over valve.

[0012] The invention is explained in greater detail using threeexemplary embodiment and the associated Figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 shows a cross-sectional view of an embodiment of aventilation in a fuel tank;

[0014]FIG. 2 shows the plan view of an embodiment of a ventilationdevice;

[0015]FIG. 3 shows the plan view of another embodiment of a ventilationdevice having four ventilation lines.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0016] The fuel tank 1, as shown in FIG. 1, has a compensator reservoir2 right below the upper fuel tank wall 12. The compensator reservoir 2extends essentially from a first side wall 3 to a second side wall 4which is located opposite the first side wall 3. A first ventilationline 5 opens into the interior of the fuel tank 1 with a first opening 6close to the first side wall 3. This first ventilation line 5 entersinto a widened section 7 of the compensator reservoir 2 and runs withinthe compensator reservoir 2 until it nears the vicinity of the secondside wall 4, wherein the ventilation line 5 opens with a second opening8 into the compensator reservoir 2. A second ventilation line 9 opensinto the interior of the fuel tank 1 with a first opening 13 close tothe second side wall 4. This second ventilation line 5 enters into thewidened section 7 of the compensator reservoir 2 and continues withinthe interior of the compensator reservoir 2 until it nears the vicinityof the first side wall 3.

[0017]FIG. 2 illustrates an embodiment of the ventilation device usingfour ventilation lines. The fuel tank includes four areas from whicheach of the four ventilation lines originate. The first, second, thirdand fourth ventilation lines, (5, 9, 10 and 11, respectively) arearranged near one another in the compensator reservoir 2. The first,second, third and fourth ventilation lines 5, 9, 10, and 11,respectively, are predominantly diagonal and run diagonally from thefirst area 15, second area 16, third area 17 and fourth area 18,respectively, toward the compensator reservoir 2 and then enter into thecompensator reservoir 2 in the region of the widened section 7. Once thefirst, second, third and fourth ventilation lines 5, 9, 10, and 11,respectively, enter into the compensator reservoir 2, they are parallelto each other and are guided to either the first side wall or the secondside wall, whichever is located further from the area from which thatparticular ventilation line originated (the “opposing side wall”). Forexample, in the embodiment shown in FIG. 2, the first ventilation line 5originates in area 15 and runs diagonally towards the widened section 7of the compensator reservoir 2. Once the first ventilation line 5 entersthe compensator reservoir 2 at the widened section 7, it travels towardthe second side wall 4 and ends within the compensator reservoir 2. Thesecond ventilation line 9 originates in area 16 and runs diagonallytowards the widened section 7 of the compensator reservoir 2. Once thesecond ventilation line 9 enters the compensation reservoir 2 at thewidened section 7, it travels toward the first side wall 3 and endswithin the compensator reservoir 2. The third ventilation line 10originates in area 17 and runs diagonally towards the widened section 7of the compensator reservoir 2. Once the third ventilation line 10enters the compensation reservoir 2 at the widened section 7, it travelstoward the first side wall 3 and ends within the compensator reservoir2. The fourth ventilation line 11 originates in area 18 and runsdiagonally towards the widened section 7 of the compensator reservoir 2.Once the fourth ventilation line 11 enters the compensation reservoir 2at the widened section 7, it travels toward the second side wall 4 andends within the compensator reservoir 2.

[0018]FIG. 3 shows an embodiment of the ventilation device in a fueltank 1, wherein the ventilation device includes a compensator reservoir2 having four subarms, a first subarm 20, a second subarm 21, a thirdsubarm 22 and a fourth subarm 23. Each subarm extends into one of theareas. The first subarm 20 extends into the first area 15, the secondsubarm 16 extends into the second area 16, the third subarm 22 extendsinto the third area 17, and the fourth subarm 23 extends into the fourtharea 18. The ventilation lines each run diagonally from an area (the“originating area”), through the subarm extends into that area (the“originating subarm”) and the subarm extends into the area locateddiagonally from the area from which the ventilation line originated (the“opposing subarm”), terminating within the opposing subarm so that thatventilation line's second opening is located within the compensatorreservoir 2. For example, in the embodiment shown in FIG. 3, the firstventilation line 5 begins in area 15 and runs through subarm 20 and thenthrough subarm 22 so that the first ventilation line 5 terminates insubarm 22. The second ventilation line 9 begins in area 16 and runsthrough subarm 21 and then through subarm 23 so that the secondventilation line 9 terminates in subarm 23. The third ventilation line10 begins in area 17 and runs through subarm 22 and then through subarm20 so that the third ventilation line 10 terminates in subarm 20. Thefourth ventilation line 11 begins in area 18 and runs through subarm 23and then through subarm 21 so that the fourth ventilation line 11terminates in subarm 21.

We claim:
 1. A ventilation device for a fuel tank, wherein the fuel tankcomprises a first side wall, a second side wall and an interior,comprising: a compensator reservoir in the interior of the fuel tank;and at least two ventilation lines, wherein the at least two ventilationlines run from approximately the first side wall or the second sidewall, respectively, to approximately the second side wall or the firstside wall, respectively, within the compensator reservoir.
 2. Theventilation device as claimed in claim 1 , wherein each of the at leasttwo ventilation lines comprise a first opening and a second opening. 3.The ventilation device as claimed in claim 1 , wherein the first openingopens into the interior of the fuel tank and the second opening opensinto the compensator reservoir.
 4. The ventilation device as claimed inclaim 1 , wherein the at least two ventilation lines enter into thecompensator reservoir at one location.
 5. The ventilation device asclaimed in claim 1 , wherein the compensator reservoir comprises acenter and the at least two ventilation lines enter into the center ofthe compensator reservoir.
 6. The ventilation device as claimed in claim1 , wherein the at least two ventilation lines enter into thecompensator reservoir at different locations.
 7. The ventilation deviceas claimed in claim 1 , wherein the at least two ventilation lines arepredominantly diagonal.
 8. The ventilation device as claimed in claim 1, wherein the compensator reservoir comprises a widened sectionconnected to the interior of the fuel tank.
 9. The ventilation device asclaimed in claim 8 , wherein the widened section is connected to theinterior of the fuel tank via an ejector and/or a valve.
 10. Theventilation device as claimed in claim 8 , wherein the widened sectionis connected to the interior of the fuel tank via a fuel pump.
 11. Theventilation device as claimed in claim 1 , wherein a roll-over valve andan activated carbon filter are arranged in the compensator reservoir.12. The ventilation device as claimed in claim 1 , wherein the fuel tankfurther comprises a fuel level and may assume a plurality of inclinedpositions, wherein the at least two ventilation lines each comprise afirst opening and are arranged in such a manner that at least either oneof the first openings of the ventilation lines is situated above thefuel level for all the plurality of inclined positions of the fuel tank.13. A ventilation device for a fuel tank, wherein the fuel tank includesat least four areas and at least two opposing side walls, comprising: acompensator reservoir in the interior of the fuel tank; and at leastfour ventilation lines, wherein each of the at least four ventilationlines run from one of the at least four areas toward the compensatorreservoir, wherein each of the at least four ventilation lines enter thecompensator reservoir and are guided toward one of the opposing sidewalls.
 14. A ventilation device as claimed in claim 13 , wherein thecompensator reservoir comprises a widened section and wherein the atleast four ventilation lines enter the compensator reservoir at thewidened section.
 15. A ventilation device for a fuel tank, wherein thefuel tank comprises at least four areas, wherein each of the at leastfour areas may be an originating area, comprising: a compensatorreservoir, wherein the compensator reservoir comprises at least foursubarms, wherein each of the at least four subarms may be an originatingsubarm and/or an opposing subarm; and at least four ventilation lines,wherein each of the at least four ventilation lines run from one of theoriginating areas, through one of the originating subarms and one of theopposing subarms.
 16. A ventilation device as claimed in claim 15 ,wherein the at least four ventilation lines each include a secondopening which is located within one of the at least four opposingsubarm.